C++ INTERNAL_SYSCALL_DECL函数代码示例

int
pthread_sigmask (int how, const sigset_t *newmask, sigset_t *oldmask)
{
  sigset_t local_newmask;

  /* The only thing we have to make sure here is that SIGCANCEL and
     SIGSETXID is not blocked.  */
  if (newmask != NULL
      && (__builtin_expect (__sigismember (newmask, SIGCANCEL), 0)
	  || __builtin_expect (__sigismember (newmask, SIGSETXID), 0)))
    {
      local_newmask = *newmask;
      __sigdelset (&local_newmask, SIGCANCEL);
      __sigdelset (&local_newmask, SIGSETXID);
      newmask = &local_newmask;
    }

#ifdef INTERNAL_SYSCALL
  /* We know that realtime signals are available if NPTL is used.  */
  INTERNAL_SYSCALL_DECL (err);
  int result = INTERNAL_SYSCALL (rt_sigprocmask, err, 4, how, newmask,
				 oldmask, _NSIG / 8);

  return (INTERNAL_SYSCALL_ERROR_P (result, err)
	  ? INTERNAL_SYSCALL_ERRNO (result, err)
	  : 0);
#else
  return sigprocmask (how, newmask, oldmask) == -1 ? errno : 0;
#endif
}

/* For asynchronous cancellation we use a signal.  This is the handler.  */
static void
sighandler_setxid (int sig, siginfo_t *si, void *ctx)
{
  /* Safety check.  It would be possible to call this function for
     other signals and send a signal from another process.  This is not
     correct and might even be a security problem.  Try to catch as
     many incorrect invocations as possible.  */
  if (sig != SIGSETXID
#ifdef __ASSUME_CORRECT_SI_PID
      /* Kernels before 2.5.75 stored the thread ID and not the process
	 ID in si_pid so we skip this test.  */
      || si->si_pid != THREAD_GETMEM (THREAD_SELF, pid)
#endif
      || si->si_code != SI_TKILL)
    return;

  INTERNAL_SYSCALL_DECL (err);
  INTERNAL_SYSCALL_NCS (__xidcmd->syscall_no, err, 3, __xidcmd->id[0],
			__xidcmd->id[1], __xidcmd->id[2]);

  if (atomic_decrement_val (&__xidcmd->cntr) == 0)
    lll_futex_wake (&__xidcmd->cntr, 1);

  /* Reset the SETXID flag.  */
  struct pthread *self = THREAD_SELF;
  int flags = THREAD_GETMEM (self, cancelhandling);
  THREAD_SETMEM (self, cancelhandling, flags & ~SETXID_BITMASK);

  /* And release the futex.  */
  self->setxid_futex = 1;
  lll_futex_wake (&self->setxid_futex, 1);
}

clock_t
__times (struct tms *buf)
{
  INTERNAL_SYSCALL_DECL (err);
  clock_t ret = INTERNAL_SYSCALL (times, err, 1, buf);
  if (INTERNAL_SYSCALL_ERROR_P (ret, err)
      && __builtin_expect (INTERNAL_SYSCALL_ERRNO (ret, err) == EFAULT, 0))
    {
      /* This might be an error or not.  For architectures which have
	 no separate return value and error indicators we cannot
	 distinguish a return value of -1 from an error.  Do it the
	 hard way.  We crash applications which pass in an invalid BUF
	 pointer.  */
#define touch(v) \
      do {								      \
	clock_t temp = v;						      \
	asm volatile ("" : "+r" (temp));				      \
	v = temp;							      \
      } while (0)
      touch (buf->tms_utime);
      touch (buf->tms_stime);
      touch (buf->tms_cutime);
      touch (buf->tms_cstime);

      /* If we come here the memory is valid and the kernel did not
	 return an EFAULT error.  Return the value given by the kernel.  */
    }

  /* Return value (clock_t) -1 signals an error, but if there wasn't any,
     return the following value.  */
  if (ret == (clock_t) -1)
    return (clock_t) 0;

  return ret;
}

/* Remove message queue named NAME.  */
int
mq_unlink (const char *name)
{
  if (name[0] != '/')
    {
      __set_errno (EINVAL);
      return -1;
    }

  INTERNAL_SYSCALL_DECL (err);
  int ret = INTERNAL_SYSCALL (mq_unlink, err, 1, name + 1);

  /* While unlink can return either EPERM or EACCES, mq_unlink should
     return just EACCES.  */
  if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (ret, err)))
    {
      ret = INTERNAL_SYSCALL_ERRNO (ret, err);
      if (ret == EPERM)
	ret = EACCES;
      __set_errno (ret);
      ret = -1;
    }

  return ret;
}

int
posix_fadvise (int fd, off_t offset, off_t len, int advise)
{
  INTERNAL_SYSCALL_DECL (err);
# ifdef __NR_fadvise64
  int ret = INTERNAL_SYSCALL_CALL (fadvise64, err, fd,
				   __ALIGNMENT_ARG SYSCALL_LL (offset),
				   len, advise);
# else
#  ifdef __ASSUME_FADVISE64_64_6ARG
  int ret = INTERNAL_SYSCALL_CALL (fadvise64_64, err, fd, advise,
				   __ALIGNMENT_ARG SYSCALL_LL (offset),
				   SYSCALL_LL (len));
#  else

#   ifdef __ASSUME_FADVISE64_64_NO_ALIGN
#    undef __ALIGNMENT_ARG
#    define __ALIGNMENT_ARG
#   endif

  int ret = INTERNAL_SYSCALL_CALL (fadvise64_64, err, fd,
				   __ALIGNMENT_ARG SYSCALL_LL (offset),
				   SYSCALL_LL (len), advise);
#  endif
# endif
  if (INTERNAL_SYSCALL_ERROR_P (ret, err))
    return INTERNAL_SYSCALL_ERRNO (ret, err);
  return 0;
}

/* We can simply use the syscall.  The CPU clocks are not supported
   with this function.  */
int
__clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
		   struct timespec *rem)
{
  INTERNAL_SYSCALL_DECL (err);
  int r;

  if (clock_id == CLOCK_THREAD_CPUTIME_ID)
    return EINVAL;
  if (clock_id == CLOCK_PROCESS_CPUTIME_ID)
    clock_id = MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED);

  if (SINGLE_THREAD_P)
    r = INTERNAL_SYSCALL (clock_nanosleep, err, 4, clock_id, flags, req, rem);
  else
    {
      int oldstate = LIBC_CANCEL_ASYNC ();

      r = INTERNAL_SYSCALL (clock_nanosleep, err, 4, clock_id, flags, req,
			    rem);

      LIBC_CANCEL_RESET (oldstate);
    }

  return (INTERNAL_SYSCALL_ERROR_P (r, err)
	  ? INTERNAL_SYSCALL_ERRNO (r, err) : 0);
}

int posix_fadvise64(int fd, off64_t offset, off64_t len, int advice)
{
	INTERNAL_SYSCALL_DECL (err);
	/* ARM has always been funky. */
#if defined (__arm__) || \
    (defined(__UCLIBC_SYSCALL_ALIGN_64BIT__) && (defined(__powerpc__) || defined(__xtensa__)))
	/* arch with 64-bit data in even reg alignment #1: [powerpc/xtensa]
	 * custom syscall handler (rearranges @advice to avoid register hole punch) */
	int ret = INTERNAL_SYSCALL (fadvise64_64, err, 6, fd, advice,
			OFF64_HI_LO (offset), OFF64_HI_LO (len));
#elif defined(__UCLIBC_SYSCALL_ALIGN_64BIT__)
	/* arch with 64-bit data in even reg alignment #2: [arcv2/others-in-future]
	 * stock syscall handler in kernel (reg hole punched) */
	int ret = INTERNAL_SYSCALL (fadvise64_64, err, 7, fd, 0,
			OFF64_HI_LO (offset), OFF64_HI_LO (len),
			advice);
# else
	int ret = INTERNAL_SYSCALL (fadvise64_64, err, 6, fd,
			OFF64_HI_LO (offset), OFF64_HI_LO (len),
			advice);
# endif
	if (INTERNAL_SYSCALL_ERROR_P (ret, err))
		return INTERNAL_SYSCALL_ERRNO (ret, err);
	return 0;
}

const fenv_t *
__fe_nomask_env (void)
{
#if __ASSUME_NEW_PRCTL_SYSCALL == 0
# if defined PR_SET_FPEXC && defined PR_FP_EXC_PRECISE
  int result = INLINE_SYSCALL (prctl, 2, PR_SET_FPEXC, PR_FP_EXC_PRECISE);

  if (result == -1 && errno == EINVAL)
# endif
    {
      struct sigaction act;

      act.sa_handler = (sighandler_t) fe_nomask_handler;
      sigemptyset (&act.sa_mask);
      act.sa_flags = 0;

      sigaction (SIGUSR1, &act, &oact);
      raise (SIGUSR1);
    }
#else
  INTERNAL_SYSCALL_DECL (err);
  INTERNAL_SYSCALL (prctl, err, 2, PR_SET_FPEXC, PR_FP_EXC_PRECISE);
#endif

  return FE_ENABLED_ENV;
}

int
__feholdexcept (fenv_t *envp)
{
  fenv_union_t u;
  INTERNAL_SYSCALL_DECL (err);
  int r;

  /* Get the current state.  */
  r = INTERNAL_SYSCALL (prctl, err, 2, PR_GET_FPEXC, &u.l[0]);
  if (INTERNAL_SYSCALL_ERROR_P (r, err))
    return -1;

  u.l[1] = fegetenv_register ();
  *envp = u.fenv;

  /* Clear everything except for the rounding mode and trapping to the
     kernel.  */
  u.l[0] &= ~(PR_FP_EXC_DIV
	      | PR_FP_EXC_OVF
	      | PR_FP_EXC_UND
	      | PR_FP_EXC_RES
	      | PR_FP_EXC_INV);
  u.l[1] &= SPEFSCR_FRMC | (SPEFSCR_ALL_EXCEPT_ENABLE & ~SPEFSCR_FINXE);

  /* Put the new state in effect.  */
  fesetenv_register (u.l[1]);
  r = INTERNAL_SYSCALL (prctl, err, 2, PR_SET_FPEXC,
			u.l[0] | PR_FP_EXC_SW_ENABLE);
  if (INTERNAL_SYSCALL_ERROR_P (r, err))
    return -1;

  return 0;
}

int
__pthread_kill (pthread_t threadid, int signo)
{
  struct pthread *pd = (struct pthread *) threadid;

  /* Make sure the descriptor is valid.  */
  if (DEBUGGING_P && INVALID_TD_P (pd))
    /* Not a valid thread handle.  */
    return ESRCH;

  /* Force load of pd->tid into local variable or register.  Otherwise
     if a thread exits between ESRCH test and tgkill, we might return
     EINVAL, because pd->tid would be cleared by the kernel.  */
  pid_t tid = atomic_forced_read (pd->tid);
  if (__glibc_unlikely (tid <= 0))
    /* Not a valid thread handle.  */
    return ESRCH;

  /* Disallow sending the signal we use for cancellation, timers,
     for the setxid implementation.  */
  if (signo == SIGCANCEL || signo == SIGTIMER || signo == SIGSETXID)
    return EINVAL;

  /* We have a special syscall to do the work.  */
  INTERNAL_SYSCALL_DECL (err);

  pid_t pid = __getpid ();

  int val = INTERNAL_SYSCALL_CALL (tgkill, err, pid, tid, signo);
  return (INTERNAL_SYSCALL_ERROR_P (val, err)
	  ? INTERNAL_SYSCALL_ERRNO (val, err) : 0);
}

gid_t
__getegid (void)
{
  INTERNAL_SYSCALL_DECL (err);
#if __ASSUME_32BITUIDS > 0
  /* No error checking.  */
  return INTERNAL_SYSCALL (getegid32, err, 0);
#else
# ifdef __NR_getegid32
  if (__libc_missing_32bit_uids <= 0)
    {
      int result;

      result = INTERNAL_SYSCALL (getegid32, err, 0);
      if (! INTERNAL_SYSCALL_ERROR_P (result, err)
	  || INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
	return result;

      __libc_missing_32bit_uids = 1;
    }
# endif /* __NR_getegid32 */

  /* No error checking.  */
  return INTERNAL_SYSCALL (getegid, err, 0);
#endif
}

int
fedisableexcept (int excepts)
{
  int result = 0, pflags, r;
  INTERNAL_SYSCALL_DECL (err);

  r = INTERNAL_SYSCALL (prctl, err, 2, PR_GET_FPEXC, &pflags);
  if (INTERNAL_SYSCALL_ERROR_P (r, err))
    return -1;

  /* Save old enable bits.  */
  result = __fexcepts_from_prctl (pflags);

  pflags &= ~__fexcepts_to_prctl (excepts);
  r = INTERNAL_SYSCALL (prctl, err, 2, PR_SET_FPEXC,
			pflags | PR_FP_EXC_SW_ENABLE);
  if (INTERNAL_SYSCALL_ERROR_P (r, err))
    return -1;

  /* If disabling signals for "inexact", also disable trapping to the
     kernel.  */
  if ((excepts & FE_INEXACT) != 0)
    {
      unsigned long fpescr;

      fpescr = fegetenv_register ();
      fpescr &= ~SPEFSCR_FINXE;
      fesetenv_register (fpescr);
    }

  return result;
}

int sched_setaffinity(pid_t pid, size_t cpusetsize, const cpu_set_t *cpuset)
{
	size_t cnt;
	if (unlikely (__kernel_cpumask_size == 0)) {
		INTERNAL_SYSCALL_DECL (err);
		int res;
		size_t psize = 128;
		void *p = alloca (psize);

		while (res = INTERNAL_SYSCALL (sched_getaffinity, err, 3, getpid (),
					       psize, p),
		       INTERNAL_SYSCALL_ERROR_P (res, err)
		       && INTERNAL_SYSCALL_ERRNO (res, err) == EINVAL)
			p = extend_alloca (p, psize, 2 * psize);

		if (res == 0 || INTERNAL_SYSCALL_ERROR_P (res, err)) {
			__set_errno (INTERNAL_SYSCALL_ERRNO (res, err));
			return -1;
		}

		__kernel_cpumask_size = res;
	}

	/* We now know the size of the kernel cpumask_t.  Make sure the user
	   does not request to set a bit beyond that.  */
	for (cnt = __kernel_cpumask_size; cnt < cpusetsize; ++cnt)
		if (((char *) cpuset)[cnt] != '\0') {
			/* Found a nonzero byte.  This means the user request cannot be
			   fulfilled.  */
			__set_errno (EINVAL);
			return -1;
		}

	return INLINE_SYSCALL (sched_setaffinity, 3, pid, cpusetsize, cpuset);
}

int
setfsuid (uid_t uid)
{
  INTERNAL_SYSCALL_DECL (err);
# if  __ASSUME_32BITUIDS > 0
  /* No error checking. */
  return INTERNAL_SYSCALL (setfsuid32, err, 1, uid);
# else
#  ifdef __NR_setfsuid32
  if (__libc_missing_32bit_uids <= 0)
    {
      int result;

      result = INTERNAL_SYSCALL (setfsuid32, err, 1, uid);
      if (! INTERNAL_SYSCALL_ERROR_P (result, err)
	  || INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
	return result;

      __libc_missing_32bit_uids = 1;
    }
#  endif /* __NR_setfsuid32 */

  if (uid != (uid_t) ((__kernel_uid_t) uid))
    {
      __set_errno (EINVAL);
      return -1;
    }

  /* No error checking. */
  return INTERNAL_SYSCALL (setfsuid, err, 1, uid);
# endif
}

/* Reserve storage for the data of the file associated with FD.  */
int
posix_fallocate (int fd, __off_t offset, __off_t len)
{
#ifdef __NR_fallocate
# ifndef __ASSUME_FALLOCATE
  if (__builtin_expect (__have_fallocate >= 0, 1))
# endif
    {
      INTERNAL_SYSCALL_DECL (err);
      int res = INTERNAL_SYSCALL (fallocate, err, 4, fd, 0, offset, len);

      if (! INTERNAL_SYSCALL_ERROR_P (res, err))
	return 0;

# ifndef __ASSUME_FALLOCATE
      if (__builtin_expect (INTERNAL_SYSCALL_ERRNO (res, err) == ENOSYS, 0))
	__have_fallocate = -1;
      else
# endif
	if (INTERNAL_SYSCALL_ERRNO (res, err) != EOPNOTSUPP)
	  return INTERNAL_SYSCALL_ERRNO (res, err);
    }
#endif

  return internal_fallocate (fd, offset, len);
}